Garden Troubleshooting

Late blight of potato was responsible for the Irish potato famine of the late 1840s. Late blight is caused by the oomycete Phytophthora infestans. Oomycetes are fungus-like organisms also called water molds, but they are not true fungi. CategoryFungiSigns/SymptomsLesions appear as small dark green water…

 Powdery mildew is a common disease on many types of plants and is prevalent in many areas of California. Infection occurs when fungus contacts a suitable host and environmental conditions are favorable. Infections spread as spores produced in these white patches move by wind and splashing rain to other…

Virus transmitted by aphids. After feeding on an infected plant, aphids are only able to transmit this virus for very short periods of time (minutes to a few hours). In general, spread of potyviruses in the field occurs when aphid activity is high and is often very rapid and localized. …

In the Bay Area, the most frequently found ants populating our gardens and invading our homes are Argentine ants. Argentine ants are small (1/8”), and their queens are slightly larger. Their bodies are constricted, giving them an appearance of a thin waist, which distinguishes them from termites. …

 Small insects that suck fluids out of stems, leaves, and other tender plant parts. Soft pear-shaped bodies with long legs and antennae and may be green, yellow, brown, red, or black. A few species appear waxy or woolly due to the secretion of a waxy white or gray substance over their body surface…

Common vegetable garden pest that also attacks ripening stone fruit. Adult beetles are shiny with black heads, long antennae, and about one-quarter inch long. Striped or spotted depending on species. Larvae are whitish and slender with three pairs of short legs; the head and tip of the abdomen are darker…

 Cutworms are dull brown caterpillars one to two inches long when fully grown. They curl into a C-shape when disturbed. Some clip off seedling stems, while others chew or bore holes. CategoryInsectSigns/SymptomsCutworms feed on blossoms and leaves of many ornamental plants and attack most edible…

 Earwigs can devastate seedling vegetables or annual flowers and often seriously damage maturing soft fruit or corn silks.  They also have a beneficial role in the landscape and have been shown to be important predators of aphids. Although several species occur, the most common in California…